Router device and network system using the same

ABSTRACT

This invention provides a router device facilitating a management of connection of a managing person and assuring a communication quality of each of the connections. The router device 1 determines a communication quality required by the communication of the packet in reference to a protocol information, an application acknowledging information and a priority information, transmits the control packet having the determined communication quality set therein to another router device contained in the same connection and further performs a traffic control (a preferential processing of a packet or the like) satisfying a communication quality indicated by the transmitted or received control packet in respect to the packet of the aforesaid connection.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a router device for use in forwarding acommunication between networks.

[0002] A router device connects a plurality of networks and furtherperforms to forwarding a packet sent between the connected networks. Inaddition, the router device performs a traffic control for processingpreferentially a specified packet in order to assure a communicationquality of connection between the terminals to be communicated.

[0003] There is a certain system in which this traffic control iscarried out in accordance with the management information registered ina router device by a managing person for the network. In this system,for example, as to the terminal device for performing a communicationrequiring a real-time characteristic, managing information forinstructing a preferential processing for a packet required by theterminal device is registered in advance in the router device. However,the managing person must register managing information having the samecontents in respect to all the router devices where the packet of theconnection may pass in the case that a certain connection is to beregistered.

[0004] In turn, it has been promoted to make a standardization for aprotocol (a resource reservation protocol) capable of specifying atraffic control (assignment for a communication band) from a terminaldevice of a user in a network to a router device. In the system to whichthis protocol is applied, all the terminals in the system are providedwith a program capable of performing a communication of the protocol.When a communication is started, the transmission terminal specifies acommunication band width by the communication of the resourcereservation protocol to a terminal of a communicating party and routersforwarding the communication. The router device may perform a trafficcontrol in such a way that it may fulfill the specified communicationband width or the like. A detailed information about the aforesaidprotocol is described in “RSVP: A New Resource Reservation Protocol” L.Zhang, S. Deering, D. Estrin, S. Shenker & D. Zappala, IEEE Network1993.9.

[0005] In the system in which a managing person registers a managinginformation indicating the content of the traffic control, it isnecessary to perform a registration of the same content in respect toall the router devices through which a packet may pass for everyconnection. In the case that there are many router devices performing aforwarding, this registration may become a substantial burden for amanaging person.

[0006] Adopting the reservation protocol eliminates the need for settingthe information indicating the contents of traffic control to the routerin the communication path because the information will be transferred bythe protocol, thereby lightening the burden of the managing person.However this technique causes new problems as follows.

[0007] In a system in which a user can specify the content of trafficcontrol by the resource reservation protocol, it is necessary to installthe program capable of performing a communication of the resourcereservation protocol in all the terminals, so that a high burden may beapplied to the managing person when the system is constructed.

[0008] In addition, in this system, since all the users can specify thecommunication band width of their own connections respectively, there isa possibility that a communication band or a processing capability of arouter device is occupied by a certain connection and an opening ofother connections or communication quality can not be assured.

SUMMARY OF THE INVENTION

[0009] In view of the foregoing, it is an object of the presentinvention to provide a router device and a network system using the samein which a management of connection of a managing person may easily beattained and a communication quality of each of the connections isassured.

[0010] It is another object of the present invention to provide a routerdevice and a network system using the same in which there is providedmeans for performing a processing to be issued by a terminal device byits nature in place of the terminal device.

[0011] It is another object of the present invention to provide a routerdevice and a network system using the same in which there is providedmeans for disabling from a user setting a communication band or the likeand occupying a function of the router freely.

[0012] In order to attain the aforesaid objects, the present inventionis operated such that in the case that the terminal device has nofunction of resource reservation protocol, the router may issue acontrol packet of the resource reservation protocol in place of theterminal device.

[0013] In addition, in the case that the terminal device has a functionof resource reservation protocol, the router receives only the controlpacket sent from a terminal permitted in advance to avoid the problemthat the terminal device may freely set a communication band or the likeand a function of the router may be occupied.

[0014] More practically, the router device of the present invention isconstructed such that each of a plurality of networks having either atleast one communication terminal or at least one router device connectedthereto is connected to each other and a connection betweencommunication terminals to perform a communication through a pluralityof said networks is managed as a connection by at least two of saidrouter devices, said router device comprising: receiving means forreceiving a packet from said plurality of networks; connectionacknowledging means for acknowledging a connection to communicate withsaid packet in reference to the content of the packet received by saidreceiving means; transmission means for transferring said receivedpacket to said network corresponding to the connection acknowledged bysaid connection acknowledging means; management table having informationindicating the content of a traffic control performed in respect to saidconnection for every connection of said communication terminal connectedto said network connected to said router device without passing throughother router devices; connection management means for generating acontrol packet including information indicating said connection in thecase that the packet received by said receiving means is a packet ofnot-opened connection and information indicating the content of trafficcontrol registered in said management table in correspondent with saidconnection and transmitting the generated control packet to other routerdevices included in said connection from said transmission means;communication control means for opening said connection in response toboth information indicating a connection used for generating saidcontrol packet and information indicating the content of the trafficcontrol and for applying a traffic control to the packet transferred bysaid transmission means in respect to said connection; and registeringmeans for revising the content of registration of said management tablein response to a predetermined instruction for management.

[0015] This router device limits the content of the traffic controlperformed for each of the connections in accordance with the content ofregistration of the management table registered by a managing person fora network, for example, under application of a management instruction,resulting in that it is possible to make a proper distribution ofprocessing capability of the router device to each of the connectionsand to assure a management of each of the connections of the managingperson.

[0016] In addition, this router device facilitates a management of eachof the connections performed by a managing person due to the fact thatonly the managing table is satisfactory for the registration of theconnection with the communication terminal directly connected withoutapplying any other router devices.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be more apparent from the followingdetailed description, when taken in conjunction with the accompanyingdrawings, in which:

[0018]FIG. 1 is a block configuration figure for showing a router deviceof a first preferred embodiment of the present invention;

[0019]FIG. 2 is a hardware configuration view of a router device;

[0020]FIG. 3 is an example of a format of a packet treated by a routerdevice;

[0021]FIG. 4 is a connection management table;

[0022]FIG. 5 is a permit list and a mapping table to be set in a routerdevice;

[0023]FIG. 6 is a view of configuration of a queue classified by aquality class;

[0024]FIG. 7 is a processing flow for processing a packet receivingprocessing;

[0025]FIG. 8 is a processing flow of a packet discard processing;

[0026]FIG. 9 is a processing flow of a first discard processing;

[0027]FIG. 10 is a processing flow of a second discard processing;

[0028]FIG. 11 is a processing flow of a packet classifying processing;

[0029]FIG. 12 is a processing flow of a quality control managingprocessing;

[0030]FIG. 13 is a processing flow of a resource reservation processing;

[0031]FIG. 14 is a processing flow of a packet forwarding processing;

[0032]FIG. 15 is a processing flow of a packet transmission processing;

[0033]FIG. 16 is a processing flow of a quality control processing;

[0034]FIG. 17 is a configuration figure for showing a network system;

[0035]FIG. 18 is a hardware configuration of a router device relating toa second preferred embodiment;

DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Referring now to the drawings, some preferred embodiments of thepresent invention will be described as follows.

[0037] In FIG. 1 is illustrated a function block diagram of a routerdevice relating to a first preferred embodiment of the presentinvention.

[0038] Processing of the router device 1 shown in FIG. 1 are roughlyclassified into a packet receiving processing in which a packet isreceived for each of the classified quality and performing a discardingof it as required, a packet forwarding processing in which a packet tobe transferred is selected corresponding to a quality class, and apacket transmission processing in which a packet selected fortransferring operation is transmitted in response to a quality class. Inaddition, the router device 1 assures a communication quality of each ofthe connections by managing and restricting a transmission or areceiving and a discarding (a traffic control) of the packetcorresponding to the quality class for every connection.

[0039] In FIG. 1, the router device 1 has, as a configuration related tothe packet receiving processing, a packet receiving section 2 forreceiving the packet and storing it in a buffer (corresponding to thebuffer memory 22 in FIG. 2); a packet classifying section 3Rx forclassifying a quality class of the received packet; a connectionmanagement table 4Rx used for classifying the quality class; a buffermanagement section 5 for managing the aforesaid buffer; and a queue 6Rxclassified by quality class where the received packets are stored foreach of the quality classes. In addition, as a configuration relating tothe packet transmission processing, it has a packet classifying section3Tx, a connection management table 4Tx, a queue 6Tx classified byquality and a packet transmission section 11. In addition, the routerdevice 1 has a communication quality management section 7 for managing apacket transmission processing and a packet receiving processing, apermit list 8 and a mapping table 9 utilized in its management and apacket forwarding section 10 for performing a packet forwardingprocessing.

[0040] The packet transmitted to the router device 1 in the network isreceived at the packet receiving section 2 and stored in a vacant bufferarea in the buffer. The packet classifying section 3Rx checks if theaforesaid packet connection is registered in the connection managementtable 4Rx and if the connection is registered, it determines a qualityclass of the aforesaid packet on the basis of information in the mappingtable 9 and stores it in the queue 6Rx classified by qualitycorresponding to quality class.

[0041] In the case that the aforesaid connection is not yet registeredin the connection management table 4Rx, the communication qualitymanagement section 7 classifies it from information in the permit list 8whether or not the traffic control for the connection is permitted.Then, in the case that it is permitted, the communication qualityparameter indicating the content of the traffic control is retrieved bythe mapping table 9 to generate a control packet setting the retrievedcommunication quality parameter and then the parameter is transmitted tothe network through the packet transmission section 11. The packetforwarding section 10 preferentially takes out a packet from a queuehaving a high quality class of the queue 6Rx classified by quality,classifies an allowable forwarding/not allowable forwarding of thepacket on the basis of a transmitting address of the taken-out packetand delivers the allowable forwarding packet to the packet classifyingsection 3Tx. The packet classifying section 3Tx checks and determinesthe delivered packet quality class in reference to the connectionmanagement table 4Tx and stores it the corresponding queue 6Txclassified by quality. The packet transmission section 11 preferentiallytakes out a packet of high quality class from the queue 6Tx classifiedby quality class and transmits it to the network.

[0042] In FIG. 2 is illustrated a hardware configuration of the routerdevice 1.

[0043] In FIG. 2, the router device 1 is comprised of a CPU 20, a mainmemory 21, a buffer memory 22, a network controller 23 and an internalbus 24 for use in connecting each of the sections 20 to 23. There isprovided one network controller 23 for every network connecting to therouter device 1. The packet receiving section 2 and the packettransmission section 11 shown in FIG. 1 are realized by the processingperformed under a cooperation with the network controller 23 and the CPU20.

[0044] The packet classifying sections 3Rx, 3Tx, the buffer managementsection 5, the communication quality management section 7 and the packetforwarding section 10 shown in FIG. 1 are realized by the CPU 20. Thequeues 6Rx, 6Tx classified by quality class, the connection managementtables 4Rx, 4Tx, the permit list 8 and the mapping table 9 shown in FIG.1 are realized by the buffer memory 22 and a memory location is managedby a pointer stored in the main memory 21.

[0045] In addition, the program executed by the network controller 23and the CPU 20 is stored in the main memory 21, for example.

[0046] The program may also be retrieved from a storage medium such asfloppy, ROM, etc or from a storage of a server connected to a networkwhich is connected to the router, and stored in the main memory 21.

[0047] In FIG. 3 is illustrated a format of packet to be transmitted andreceived by the router device 1.

[0048] In FIG. 3, the packet 30 is comprised of the header section 31and the data section 32. The header section 31 is comprised of apriority information 33 for indicating a priority required by theterminal of transmission device, a protocol information 34 indicatingthe type of packet, a transmission device address information 35indicating the terminal of the transmission device, an addressingaddress information 36 indicating the terminal of the receiving deviceand a port No. information 37 for indicating an application of theterminal related to the communication. The data section 32 is comprisedof a communication data or the like generated by the application of theterminal device.

[0049] This packet 30 is used as a control packet when a communicationresource is reserved and a data packet when a data communication iscarried out, respectively. The control packet is generated throughprocessing of the resource reservation protocol and contains areservation information packet sent from either a terminal of thetransmission device or the router device 1 and a reservation requestpacket sent back from either the terminal of the receiver or the routerdevice 1. At the reservation information packet, the aforesaid protocolinformation 34, the addressing address information 36 and the port No.information 37 are set. At the reservation request packet, the protocolinformation 34 of the received reservation information packet, theaddressing address information 36 and the port No. information 37 areset and further at the data section 32 are set the communication qualityparameters.

[0050] In addition, the router device 1 may also receive the managementpacket sent from the management terminal device operated by themanagement person of the network. The management person can revise thecontent of registration of the permit list 8 and the mapping table 9 ofthe optional router device 1 through transmission of the managementpacket.

[0051] The aforesaid four kinds of packets contain information for usein classifying the type of packet. In addition, since the applicationgenerated the received packets 30 is specified in reference to the portNo. information 37, the terminal device of the receiver can receive andclassify the packets 30 of a different plurality of applications inconcurrent with each of applications. In this case, the protocolinformation 34, the addressing address information 36 and the port No.information 37 are called as connection information in total.

[0052] In FIG. 4 is illustrated one example of the set information ofthe connection management table 4. As shown in FIG. 4, the set ofconnection information (addressing address information, the protocolinformation and the port No. information) and the pointer informationfor the mapping table 9 are registered in the connection managementtable 4. The connection registered in the connection management table 4is an opened connection and a pointer indicating the packet is stored inthe queue 6 classified by quality in accordance with the content of themapping table 9 specified in response to the corresponding pointerinformation.

[0053] In FIG. 5 is illustrated one example of a set information of thepermit list 8 and the mapping table 9.

[0054] As shown in FIG. 5, in the permit list 8 are set in sets atransmission device address information, an addressing addressinformation, a permit flag and a pointer information for the mappingtable 9. “ON” is set at the permit flag of the connection of whichtraffic control is allowed and “OFF” is set at the permit flag of theconnection not allowed. There is provided one permit list 8 for everynetwork controller 23 of the router device 1 (for every receivinginterface) and then the aforesaid information about either the networkor the terminal connected to the network controller 23 is set in thepermit list 8. To the pointer information, a plurality of identifiers(to be described later) of the mapping table 9 can be set.

[0055] Sets of the identifiers, the type of protocol, the port No. andthe communication quality parameters are set in the mapping table 9. Aplurality of communication quality parameters are set in correspondencewith the value of priority of the packet 30. In the preferredembodiment, the priority classes of the processing are indicated by fourlevels (0 is a minimum and 3 is a maximum) and the discard levels areindicated by two levels (“D” shows a discard-ok and “N” shows adiscard-no). One mapping table 9 is set in the router device 1 and it iscommonly indicated by pointer information of a plurality of permit lists8. In this case, the quality classes are set in four levels and thepriority class in processing is used as a quality class as it is. Thatis, the packet having a processing priority level of 3 also shows thatthe quality class may become 3 and it is processed at the highestpriority in the forwarding processing of the packet as well as thetransmission processing of the packet.

[0056] In the example shown in FIG. 5, all the packets with <theprotocol A and the port No. w> can be discarded and the processingpriority is 0 in the case of 0 to 3 of the priority information and thisis as low as 1 in the case of the priority information of more than 3.That is, this packet is suitable for a communication of batch typeapplication where its retransmission caused by discarding of the packetor the delay in transmission is allowed. The packet of <B, x> is notprocessed on the priority information, but always processed at thehighest priority and can not be discarded. This packet is suitable for acommunication of application of a basic work for performing an on-lineprocessing. The packets of <C, y> and <C, z> are processed at thehighest priority in the case that there are more than one priorityinformation. A discarding level is set such that all the <C, z> are notallowed and <C, y> can be discarded in the case that the priorityinformation is less than 3. That is, the packet of <C, y> is suitablefor a transmission in a real time basis and a transmission of data (forexample, audio sound information) capable of permitting a certainreduction in transmission quality. The packet of <C, z> is suitable fora transmission of data (for example, a motion information) on a realtime basis in which a reduction in transmission quality is morepermitted.

[0057] In FIG. 6 is illustrated an example of configuration of each ofqueues 6Rx, 6Tx classified by quality.

[0058] Each of the queues 6Rx, 6Tx classified by quality contains aqueue of the received packet which is classified depending on itsquality class and connection. In FIG. 6 is indicated a state in whichqueue rows of the three connections in a certain quality class (n) arestored. Each of the quality classes has a connection pointer section 82and a row of queue storing buffer 84 (a connection queue 87) for everyconnection.

[0059] The connection pointer section 82 is comprised of a pointer 82 afor indicating a connection pointer 82 becoming a forwarding target, apointer 82 b for indicating the connection pointer 82 becoming adiscarded item next and a pointer 82 c for indicating a leading queuestoring buffer 84 and a last queue storing buffer 84 for its ownconnection.

[0060] A processing connection list 85 is formed by the pointer 82 a anda discard connection list 86 is formed by the pointer 82 b. Within thequeue storing buffer 84 are stored the packet and the pointer 88 forindicating the queue storing buffer 84 across the packet. In this case,within the leading queue storing buffer 84 is stored the packet not yetprocessed and having the oldest receiving time and subsequently thepackets are stored in order of newer being received to the end of thequeue storing buffer 84. In addition, the connection pointer section 82acting as the forwarding target and the discard target is pointed byeach of the processing connection pointer 80 and the discard connectionpointer 81, respectively.

[0061] When a connection becoming as a target to be traffic controlledis newly registered, the connection pointer 82 is added, the packetbelonging to the connection is stored in the connection queue 87 of theadded connection pointer 82. In the processing at each of the qualityclasses, the packets are processed one by one in sequence for everyconnection. This processing prevents only a packet of a certainspecified connection from being processed in the case that manyconnections are present in the same quality class and enables all theconnections to be equally processed. In this case, on completion ofprocessing of the packet, the aforesaid pointer is revised and thepacket is deleted from the connection queue.

[0062] A processing of the router device 1 will be described as followsin reference to the processing flow chart.

[0063] In FIG. 7 is indicated a processing flow of the packet receivingprocessing.

[0064] Upon receiving the packet, the packet receiving section 2 of therouter device 1 stores the packet in the vacant buffer area of thebuffer memory 22 specified by the buffer management section 5 (100). Thebuffer management section 11 always monitors a capacity of the vacantbuffer area in the buffer memory 22 and classifies if the capacity isnot less than a specified value (101). In the case that the capacityvalue is lower than the specified value, a packet discarding processingis carried out (102). In the case that the capacity of the vacant bufferarea of the buffer memory 22 is not less than a specified value andafter the processing of the step 102, the packet classifying processing(103) is carried out to complete the processing.

[0065] In FIG. 8 is indicated a processing flow of the packet discardingprocessing 102. The communication quality management section 7classifies a degree of overlapping on the basis of the vacant bufferarea of the buffer memory 22 and performs any one of the two discardingcontrols. If the capacity of the vacant buffer area in the buffer memory22 is not less than a predetermined minimum value (a first thresholdvalue) (200), a first discarding control is carried out (201), and inthe case that the value is lower than a predetermined minimum value, asecond discarding control is carried out (202). That is, in the casethat a degree of overlapping is low (i.e. there is a surplus amount in avolume of vacant buffer area in the receiving buffer), the firstdiscarding control is carried out and in turn in the case that thedegree of overlapping is high, the second discarding control is carriedout.

[0066] In FIG. 9 is shown a processing flow chart of the firstdiscarding processing.

[0067] At the first discarding processing, the communication qualitymanagement section 7 selects the quality class having the largest totalnumber of bytes as a target of discarding control (210). Then, theconnection queue which can be discarded in the selected quality class isselected (211). As shown in FIG. 6, in the queue 6Rx classified byquality is stored the discard connection pointer 81 indicating theconnection of a target to be discarded. It is checked if the packet ispresent in the connection queue pointed by this pointer (212) and if itis present, the packet is discarded.

[0068] In addition, in the case that the packet of the terminal forperforming a re-transmission of the packet (or application) is discardedand the packet of the old receiving time stored at the extremity end ofthe connection queue is discarded, all the packets subsequent to thediscarded packet are retransmitted and there is a possibility that theoverlapping is promoted. However, in the case of the communication ofthe packet requiring a real time characteristic, the old packet in whichthe specified period of time elapsed can be eliminated, resulting inthat it is preferable that the old packet is discarded as much aspossible. Due to this fact, it is classified in the present processingif the packet is to be retransmitted as described above when the packetis discarded (213), the last packet of the connection queue is discardedif the packet is one to be retransmitted (214) and in turn if the packetis not retransmitted, the packet at the extremity end of the connectionqueue is discarded (215).

[0069] Further, since it is possible to classify it by the appliedprotocol if the packet is to be retransmitted, either the packetclassifying processing or the quality management processing adds a flagto indicate a presence or a non-presence of retransmission to the queuepointer section 82, thereby the discrimination at the step 213 becomespossible.

[0070] In the case that the packets are discarded, the packets arediscarded one by one for each of the connections of the selected qualityclass. When the packet of the connection indicated by the discardconnection pointer 81 is discarded, a presence or a non-presence of thenot-yet-processed connection is checked with a next connection queueindicated by the discard connection list 85 (216) and when theconnection is present, the connection is registered in the discardconnection pointer 81 and the operation returns back to the step 212.When the discarding processing for all the discard connection queues ofthe selected quality class is completed, a vacant capacity of the buffermemory 22 is checked (217) and if the capacity is not less than thespecified value (the second threshold value), the processing iscompleted. If the capacity is lower than the specified value, a presenceor a non-presence of the discard-ok packet is checked (218), and in turnif the packet is present, the operation returns to the step 210, thequality class having the largest total number of bytes in the registeredpacket is selected and the aforesaid discarding processing is repeated.

[0071] At the step 218, if there is no discard-ok packet, the processingis completed.

[0072] In FIG. 10 is indicated a processing flow chart of a seconddiscarding processing. In this processing, the communication qualitymanagement section 7 selects the quality class accumulating the largesttotal number of bytes in the packet as a target for discarding controlin the same manner as that of the first discarding control (230) andselects the connection queue indicated by the discarding connectionpointer 81 (231). Then, all the packets registered in the selectedconnection queue are discarded (232). In the case that thenot-yet-discarded packet is present in the quality class (233), theconnection queue indicated by the discard connection list 86 is selectedas a discard target (234) and then the operation returns to the step232. When all the packets of the aforesaid quality class have beendiscarded (233) so as to check if a capacity of the vacant buffer areain the buffer memory 22 is not less than the minimum value (a firstthreshold value) 234) and if the value is not less than the minimumvalue, the second discarding control is completed (235). In the casethat the value is lower than the minimum value, it is checked if thediscard-ok packet is present in another connection (236). If the packetis present, the operation returns back to the step 230 and thediscarding processing is repeated with the quality class having thelargest total number of bytes being applied as discarding targets.

[0073] In FIG. 11 is indicated a processing flow chart of the packetclassifying processing (103).

[0074] In this processing, the packet classifying section 3Rx classifiesit from the protocol information 34 (110) whether or not the receivedpacket is a data packet and in the case that the received packet is nota data packet, it classifies if the packet is a control packet or amanagement packet (118). In the case that the packet is the controlpacket, the resource reservation processing (to be described later 111)is carried out to complete the processing. In the case that the packetis the management packet for the router device 1 by itself, theregistered contents in the permit list 8 and the mapping table 9 arerevised in response to the set information so as to complete theprocessing (119). In the case that the packet is classified as the datapacket at the step 110, connection information (addressing addressinformation, protocol information and port No. information) is extractedfrom the packet (112) and it is checked if that information isregistered in the connection management table 4Rx (113).

[0075] In the case that the packet is already registered, the priorityinformation is extracted from the packet (115), and the quality class ofthe aforesaid packet corresponding to the extracted priority informationin the mapping table 9 indicated by the pointer information registeredin sets in the connection management table 4Rx is determined (116).Then, the aforesaid packet is stored in the queue 6Rx classified byquality for the determined quality class and the pointer indicating thestoring position is registered (117) to complete the processing.

[0076] At the step 113, in the case that the packet is not registeredyet in the connection management table 4Rx, the communication qualitymanagement processing (to be described later at 114) is carried out tocomplete the processing.

[0077] In FIG. 12 is indicated a processing flow chart of the qualitycontrol management processing (114). This processing is carried out forthe data packet not registered in the connection management table 4Rx.During this processing, the communication quality management section 7checks whether or not the received data packet is allowed for thecommunication quality assuring control in reference to the permit list 8on the basis of the transmission device address information 35 and theaddressing address information 36 set in the packet (130). In the casethat the corresponding permit flag is set “ON”, the protocol information34 and the port No. information 37 of the packet are extracted (131),and in the case that the same information is set in the correspondingmapping table 9 (132), the reservation information packet including theconnection information of that packet is transmitted to the receiverside (133). At the step 130, in the case that the permit flag is “OFF”,the processing is completed.

[0078] In FIG. 13 is indicated a flow chart of the resource reservationprocessing (111). This processing is carried out for the receivedcontrol packet. At first, it is classified whether or not the receivedcontrol packet is a packet issued from another router or a packet issuedfrom a terminal device (150). This discrimination can be classified bychecking the transmission device address information 35 of the controlpacket and by attaining whether or not the address is an address of thenetwork directly connected to the router received the control packet. Inthe case that the control packet is a packet issued from another router,it is classified that the control packet is either the reservationinformation packet or the reservation control packet request packet inreference to the type field of the packet type contained in the packetformat defined by the aforesaid resource reservation protocol (151).

[0079] If the packet is the reservation information packet, the resourcereservation protocol processing is carried out (152), the connectioninformation contained in the reservation information packet is extracted(153) and it is checked if the extracted information is registered inthe permit list 8 (154). In the case that the packet is alreadyregistered, the communication quality parameter is determined by thecorresponding mapping table 9 (155). Then, the reservation requestpacket is generated using the determined communication qualityparameters and the generated reservation request packet is transmittedto the router device 1 (or a terminal) to which the reservationinformation packet has already been transmitted (156). Thus, informationof the reservation information packet is registered in the connectionmanagement table 4 (157) in such a manner that the traffic control basedon the communication quality parameter may be subsequently carried outwith the communication of connection specified by the reservationinformation packet and the processing is completed.

[0080] In the case that the connection information is not registered inthe permit list 8 at the step 154, the reservation information packet istransferred (160) and the processing is completed. In the case that thereceived control packet is a reservation request packet at the step 151,it is checked if the reservation information packet having the samecontent as that of the connection information set in the reservationrequest packet has been transmitted (161). In the case that thereservation information packet has already been transmitted, a protocolprocessing in respect to the reservation request packet is carried out(162), a registration is carried out in the management table 4 on thebasis of the set information of the reservation request packet (157) andthe processing is completed.

[0081] In the case that the received control packet is issued from theterminal at the step 150, the control packet transmission device addressinformation 35 and the addressing address information 36 are extractedand it is checked if they are registered in the permit list 8 (158). Ifthey are registered, the resource reservation protocol processing iscarried out (159), the received control packet is transferred to thereceiving side router device 1 (or the terminal) (160) and theprocessing is completed. In the case that they are not registered in thepermit list 8, it is judged that the packet is of a connection notallowed for the communication quality assuring control, thereby noprocessing is carried out and the processing is completed.

[0082] Next, a packet forwarding processing and a packet transmissionprocessing of the router device 1 will be described as follows.

[0083] In FIG. 14, a processing flow chart of the packet forwardingprocessing is shown. During this processing, the packet forwardingsection 10 may select a packet to be forwarded by a quality controlprocessing to be described later (170). It is determined which networkcontroller is used in transmission and if a forwarding with the networkcontroller can be performed or not in reference to the addressingaddress information of the selected packet (171) and the aforesaidpacket classifying processing (FIG. 8) for the packet which can beforwarded is performed (103). However, during this processing, thereservation information packet and the reservation request packet arenot generated and not transmitted.

[0084] In FIG. 15 is shown a processing flow chart of the packettransmission processing. During this processing, the packet transmissionsection 11 selects a packet to be transmitted by the quality controlprocessing to be described later (170) and transmits the selected packet(175).

[0085] In FIG. 16 is shown a processing flow chart of a quality controlprocessing (170).

[0086] During this processing, the number of bytes which can beprocessed continuously is restricted for each of quality classes of thequeue 6 classified by quality class so as to prevent a packet having alow quality class from not being processed in the case that a largenumber of packets having a high quality class are received continuously.In addition, also in the case that a packet having a certain qualityclass is processed continuously, the packets are selected one by one foreach connection so as to prevent only a packet having a certainconnection from being processed.

[0087] At first, a maximum value Mi (i=0, 1, 2, 3) of the number ofprocessing bytes for each of the quality classes is set (191). 0 is setin a counter for obtaining a total number Bi of the processed bytes foreach of the quality classes (180). Numeral 3 indicating the highestquality class is set in a variable (n) indicating a quality class to beprocessed (181). It is checked if a packet is present in the queue ofquality class of n-th order (182). If the packet is present, it ischecked if the number of bytes Bn of the n-th order quality classexceeds the maximum value Mn of the corresponding quality class (183).If the value does not exceed the maximum value, a connection queue whichhad been registered most earlier in the n-th order quality class isdetermined (184). One of the packets is taken out of the determinedconnection queues (185) and the number of bytes of the taken-out packetis added by the counter to the number of processing bytes Bn (186). Aconnection list is checked and a connection queue to be processed nextis stored. In the case that the number of bytes 1og Bn exceeds themaximum value Mn at the step 183, a packet having a lower quality classthan before is processed.

[0088] That is, if (n) is not 0 (188), (n) is decreased (189) and theprocessing is returned back to the step 182. If (n) is 0, the number ofprocessing bytes in each of the quality classes is set to 0, and theoperation is returned back to the step 181.

[0089] Although the router device 1 performs the quality controlprocessing (170) during both packet forwarding processing and packettransmission processing, it is possible to assure communication qualityalso in the case that the communication quality assuring control iscarried out only with the packet transmission processing. In addition,it is possible to connect more than two networks by increasing thenetwork controller 23 and to perform a communication.

[0090] Next, the network system using the router device 1 will bedescribed as follows.

[0091] In FIG. 17 is illustrated an example of configuration of thenetwork system.

[0092] The network system shown in FIG. 17 includes four networks 15A,15B, 15C and 15Z and each of the networks 15A, 15B and 15C is connectedto the network 15Z through each of the router devices 1 (1A, 1B, 1C). Atleast one terminal 16A, 16B and 16C connected to each network 15A, 15Band 15C respectively and further to the network 15Z is connected anetwork management terminal 17 for performing a circuit troublemanagement for the network system, router trouble management, setting ofconfiguration definition information and collection laid of managementinformation. It is defined that the network management terminal 17 canperform a setting in the permit list 8 and the mapping table 9 of therouter device 1 through a management packet generated under theprocessing of the protocol (or the remote access) for the networkmanagement. Connection information including a transmission deviceaddress information indicating a terminal 16A of the network 15A andaddressing address information indicating a terminal 16B of the network15B is set in the permit lists 8 of the router devices 1A and lB throughthis function and the corresponding permit flag is set to “ON”. Inaddition, it is defined such that a setting of the aforesaid connectioninformation is not set in the permit lists 8 of the router devices 1AZand 1BZ.

[0093] When a data packet is transmitted from the terminal 16A to theterminal 16B under a state in which the connection is not registered,the router device 1A may generate a reservation information packet fromthe packet connection information to transmit the packet to the terminal16B due to the fact that the permit flag of the permit list 8corresponding to the address information of the packet is “ON”.

[0094] The router device 1B received this packet determines qualityparameters on the basis of the set information of the reservationinformation packet and registers the connection in the connectionmanagement table 4 due to the fact that the address information of thereceived reservation information packet has already been registered inthe permit list 8 of its own router device 1B. Then, the reservationrequest packet including the determined quality parameters andconnection information is transmitted to the terminal 16A. At the routerdevice 1A, the connection information indicated by the receivedreservation request packet is coincided with the connection informationof the reservation information packet transmitted previously by its ownrouter device 1A, so that the connection is registered in the connectionmanagement table 4. Other router devices 1AZ and 1BZ for forwardingthese control packets have no setting of the aforesaid connection in thepermit lists 8, so that all the received control packets are normallyprocessed and transferred. With such an arrangement as above,subsequently, the traffic control corresponding to the aforesaid qualityparameters is carried out for the communication between the terminal 16Aand 16B.

[0095] In turn, in the case that the terminals 16A and 16B have afunction for processing the resource reservation protocol, bothaforesaid registration of connection and the traffic control are carriedout also through transmission and receiving of the control packets ofthe terminals 16A and 16B. In this case, determination of thecommunication quality parameter is carried out by the terminal 16A or16B and the router devices 1A and 1B perform a traffic controlcorresponding to the communication quality parameters.

[0096] The permit flags of the permit lists 8 of the router devices 1Aand 1C for the connection across the networks 15A and 15C are set to“OFF”, resulting in that a traffic control over a communication betweenthe networks 15A and 15C is not carried out. In this case, the controlpacket transmitted from the terminal 16C toward the terminal 16A or 16Bis discarded at the router 1 device 1C.

[0097] As described above, the router device 1 restricts an opening ofeach of the connections or a content of traffic control applied to thecommunication of each of the connections on the basis of the content ofthe permit list 8 and the mapping table 9 registered by the managingperson to enable the communication quality of each of the connections tobe assured.

[0098] In addition, in the case that the packet of the connection notopened is transmitted, the router device 1 determines the content of thetraffic control requested by the communication of the packet inreference to the content of the mapping table 9 and informs it to allthe router devices included in the aforesaid connection, resulting inthat it is also possible to open the connection and control the propertraffic control also for the terminal having no function of the resourcereservation protocol.

[0099] Additionally, since the router device 1 requires a registrationof the permit list 8 and the mapping table 9 only for the connection ofterminal directly connected without other router devices, it is possibleto facilitate a management of the connection of the managing person ascompared with the prior art requiring a registration for all routerdevices contained in the connection.

[0100] In FIG. 18 is illustrated a hardware configuration of a routerdevice 70 relating to a second preferred embodiment of the presentinvention. The router device 70 is comprised of a CPU 60 for exclusivelyperforming a management of each of the sections of the router device 2;a memory 61 for storing a program or other management data of the CPU60; a plurality of memory cards 62; and an internal bus 66 for use inconnecting each of these sections 60 to 62. There is one memory card 62for every network connected to the router device 70 and it contains aCPU 63, a memory 64, and a network controller 65.

[0101] The router device 70 has the same functions (refer to FIG. 1) asthose of the router device 1 in the first preferred embodiment. That is,in the router device 2, the packet receiving section 2 shown in FIG. 1is realized by the network controller 65 and the CPU 63 put in theinterface card 62 receiving the packet. The packet classifying section3Rx and the packet forwarding section 10 are realized by the CPU 63stored in the interface card 62 received the packet. The packetclassifying section 3Tx is realized by the CPU 63 stored in theinterface card 62 for transmitting the packet and the packettransmission section 11 is realized by the CPU 63 and the networkcontroller 65 stored in the interface card 62 for transmitting thepacket. A queue 6Rx classified by quality class is realized by a memory64 stored in the interface card 61 received the packet, and a queue 6Txclassified by quality class is realized by a memory 64 stored in theinterface card 61 for transmitting the packet, respectively. Each of theconnection management tables 4Rx and 4Tx is realized by the memorystored in each of the interface cards 62 for transmitting and receivingthe packet, respectively. The communication quality management section 7is realized by the CPU 60, and the permit list 8 and the mapping table 9are realized by the memory 61, respectively. The mapping table 9 mayalso be realized by the memory 64 of each of the interface cards 62.

[0102] Next, a processing of the router device 70 will be described asfollows. Each of the packet classifying processing and the qualitycontrol management processing is the same as those shown in FIGS. 11 and12, respectively. In the resource reservation processing, the connectioninformation in the packet for performing the traffic control isregistered in the connection management information table 4 of theinterface card 62 for receiving the packet during the processing shownin FIG. 13. In the packet forwarding processing as shown in theprocessing in FIG. 14, the interface card 62 utilized in thetransmission is determined and the packet is transferred to it. Thetransmission and receiving processing of the packet may also similarlycarried out in each of the interface cards 62 in the same manner asthose shown in FIGS. 7 and 15.

[0103] According to this preferred embodiment as above, the same effectas that of the first preferred embodiment can be attained. In addition,since the transmission or receiving processing of the packet and theprocessing load in the forwarding processing are distributed to aplurality of CPUs 63 and 60 as well as a plurality of networkcontrollers 65, it is possible to increase a processing capability thanthat of the first preferred embodiment.

[0104] According to the present invention, it is possible to provide arouter device and network system using the same capable of facilitatinga management of the connection of a managing person and assuring acommunication quality of each of the connections.

[0105] While the present invention has been described in detail andpictorially in the accompanying drawings it is not limited to suchdetails since many changes and modifications recognizable to those ofordinary skill in the art may be made to the invention without departingfrom the spirit and the scope thereof.

We claim:
 1. A router device constructed such that each of a pluralityof networks having either at least one communication terminal or atleast one router device connected thereto is connected to each other anda connection between communication terminals to perform a communicationthrough a plurality of said networks is managed as a connection by atleast two of said router devices, said router device comprising:receiving means for receiving a packet from said plurality of networks;connection acknowledging means for acknowledging a connection tocommunicate with said packet in reference to the content of the packetreceived by said receiving means; transmission means for transferringsaid received packet to said network corresponding to the connectionacknowledged by said connection acknowledging means; management tablehaving information indicating the content of a traffic control performedin respect to said connection for every connection of said communicationterminal connected to said network connected to said router devicewithout passing through other router devices; connection managementmeans for generating a control packet including information indicatingsaid connection in the case that the packet received by said receivingmeans is a packet of not-opened connection and information indicatingthe content of traffic control registered in said management table incorrespondent with said connection and transmitting the generatedcontrol packet to other router devices included in said connection fromsaid transmission means; communication control means for opening saidconnection in response to both information indicating a connection usedfor generating said control packet and information indicating thecontent of the traffic control and for applying a traffic control to thepacket transferred by said transmission means in respect to saidconnection; and registering means for revising the content ofregistration of said management table in response to a predeterminedinstruction for management.
 2. A router device as set forth in claim 1,wherein: the traffic control performed by said communication controlmeans comprises a control for discarding a part of the packets to betransferred and a control for changing an order of transferring of thepackets to be transferred; and the content of the traffic control forevery connection registered in said management table indicates adiscard-ok or a discard-no state of the packet of said connection and apriority degree of transferring order of said packet.
 3. A router deviceas set forth in claim 1, further comprising a permit list indicatingeither an allowed opening or not-allowed opening of said connection forevery connection; and wherein said connection management means checks acontrol packet transmitted from a terminal connected to the routerdevice without passing through other router device for opening itsconnection using said permit list; and discards the packet transmittedfor the connection not allowed for its opening without any processing.4. A router device as set forth in claim 1, wherein: said connectionacknowledging means acknowledges the type of said received packet; saidmanagement table has information indicating the content of the trafficcontrol for said every connection which is registered for every type ofsaid packets; and said connection management means generating saidcontrol packet using information indicating the content of the trafficcontrol registered in said management table in correspondence with thetypes of the connection and the packet acknowledged by said connectionacknowledging means.
 5. A router device as set forth in claim 4,wherein: said packet includes a protocol information indicating aprotocol used in communication of said packet and an applicationinformation indicating an application of said communication terminal forprocessing the content of said packet; and said connection acknowledgingmeans acknowledges the type of packet in response to said protocolinformation and the application information.
 6. A router device as setforth in claim 5, wherein: said packet includes a priority informationdesired by a terminal device transmitting said packet, the priorityinformation indicating a degree of priority of the processing on saidpacket; and said connection acknowledging means acknowledges the type ofpacket in reference to said priority information.
 7. A router deviceconstructed such that each of a plurality of networks having either atleast one communication terminal or at least one router device connectedthereto is connected to each other and a connection betweencommunication terminals to perform a communication through a pluralityof said networks is managed as a connection by at least two of saidrouter devices, said router device comprising: receiving means forreceiving a packet from said plurality of networks; connectionacknowledging means for acknowledging a connection to communicate withsaid packet in reference to the content of the packet received by saidreceiving means; transmission means for transferring said receivedpacket to said network corresponding to the connection acknowledged bysaid connection acknowledging means; a management table havinginformation indicating the content of a traffic control performed inrespect to said connection for every connection of said communicationterminal connected to said network connected to said router devicewithout passing through other router devices; a permit list indicatingeither an allowed opening or not-allowed opening of said connection forthe connection; connection management means for checking a controlpacket transmitted from a terminal connected to the router withoutpassing through other router devices for opening its connection usingsaid permit list and discarding the packet transmitted for theconnection not allowed for its opening without any processing;communication control means for opening said connection allowed for itsopening in said permit list in response to information contained in saidcontrol packet received by said receiving means and for applying atraffic control to the packet transferred by said transmission means inrespect to said connection in response to information indicating thecontent of the traffic control; and registering means for revising thecontent of registration of said management table in response to apredetermined instruction for management.
 8. A router device as setforth in claim 7, wherein: the traffic control performed by saidcommunication control means comprises a control for discarding a part ofthe packets to be transferred and a control for changing an order oftransferring of the packets to be transferred; and the content of thetraffic control for every connection registered in said management tableindicates a discard-ok or a discard-no state of the packet of saidconnection and a priority degree of transferring order of said packet.9. A router device as set forth in claim 7, wherein: said connectionacknowledging means acknowledges the type of said received packet; saidmanagement table has information indicating the content of the trafficcontrol for said every connection which is registered for every type ofsaid packets; and said connection management means generating saidcontrol packet using information indicating the content of the trafficcontrol registered in said management table in correspondence with thetypes of the connection and the packet acknowledged by said connectionacknowledging means.
 10. A router device as set forth in claim 9,wherein: said packet includes a protocol information indicating aprotocol used in communication of said packet and an applicationinformation indicating an application of said communication terminal forprocessing the content of said packet; and said connection acknowledgingmeans acknowledges the type of packet in response to said protocolinformation and the application information.
 11. A router device as setforth in claim 10, wherein: said packet includes a priority informationdesired by a terminal device transmitting said packet, the priorityinformation indicating a degree of priority of the processing on saidpacket; and said connection acknowledging means acknowledges the type ofpacket in reference to said priority information.
 12. A network systemhaving of a plurality of networks each being connected to at least onecommunication terminal and at least two router devices for connectingsaid networks to each other, said network system comprising: at leastone management terminal for transmitting a managing packet for managingthe networks; and wherein said at least one management terminalgenerates a managing packet including information for a permit list insaid router devices indicating either an allowed opening or not-allowedopening of a connection for every connection and information for amanagement table in said router devices indicating the content of atraffic control performed for said every connection of saidcommunication terminals and transmits the managing packet to the routerdevices; and wherein said router devices comprises registering means forrevising the content of said permit list and said management table inresponse to said information included in said managing packet.
 13. Anetwork system according to claim 12, wherein: the router deviceconnected to the communication terminal of transmitter generates acontrol packet for requesting traffic control in response to receiving adata packet of not-opened connection whose opening is allowed in saidpermit list and transmits the packet for traffic control; and the routerdevice connected to the communication terminal of receiver generates acontrol packet for response in response to receiving the packet forrequesting traffic control for registered connection in said permit listand transmits the packet for response.
 14. A router device comprising aprocessor; a memory for storing a program to be executed by theprocessor; a network controller connected to a network for receiving andtransmitting packets; a buffer memory for storing packets received andtransmitted by the network controller; said memory having a managementtable which has information indicating the content of a traffic controlperformed for every connection respectively of a communication terminalconnected to said router device without passing through other routerdevices; wherein said processor when executing said program performs: astep for receiving a packet from said network; a step of acknowledging aconnection to communicate the packet in reference to the content of thepacket; a step for generating a control packet including informationindicating said connection in the case that the received packet is apacket of not-opened connection and information indicating the contentof traffic control registered in said management table in correspondentwith said connection ;and a step for transmitting the generated controlpacket to other router devices included in said connection from saidtransmission means.
 15. A router device according to claim 14, furthercomprising a permit list indicating either an allowed opening ornot-allowed opening of said connection for every connection; and whereinsaid processor when executing said program after said acknowledging stepfurther performs; a step of for checking whether or not opening of saidconnection is allowed in reference to said permit list.
 16. A routerdevice as set forth in claim 14, wherein: said management table storedin said memory has information indicating the content of the trafficcontrol for said every connection which is registered for every type ofsaid packets; and wherein said processor when executing said programfurther performs: a step of acknowledging the type of said receivedpacket; and a step of generating said control packet using theinformation indicating the content of the traffic control registered insaid management table in correspondence with the types of the connectionand the packet acknowledged.
 17. A router device as set forth in claim16, wherein: wherein said acknowledging step includes: a sub step ofacknowledging the type of said received packet in response to a protocolinformation indicating a protocol used in communication of said packetand an application information indicating an application of acommunication terminal for processing the content of said packet.
 18. Arouter device as set forth in claim 17, wherein: wherein saidacknowledging step further includes: a sub step of acknowledging thetype of packet in reference to a priority information included in saidreceived packet, the priority information desired by a terminal devicetransmitting said packet indicates a degree of priority of theprocessing on said packet.
 19. A computer program stored on a storagemedium, for routing a packet in a network, said computer program whenexecuted by a computer causes said computer to perform the steps of:receiving a packet from said network; acknowledging a connection tocommunicate the packet in reference to the content of the packet;generating a control packet including information indicating saidconnection in the case that the received packet is a packet ofnot-opened connection and information indicating the content of trafficcontrol registered in a management table in correspondent with saidconnection, said management table has information indicating the contentof a traffic control performed in respect to said connection for everyconnection of a communication terminal connected to said networkconnected said router device without passing through other routerdevices; and transmitting the generated control packet to other routerdevices included in said connection from said transmission means.
 20. Acomputer program according to claim 19, after the acknowledging step,further causing said computer to perform the step of: checking whetheror not opening of said connection is allowed in reference to a permitlist indicating either an allowed opening or not-allowed opening of saidconnection for every connection.
 21. A computer program according toclaim 19, after the acknowledging step, further causing said computer toperform the step of: acknowledging the type of said received packet; andgenerating said control packet using the information indicating thecontent of the traffic control in correspondence with the types of theconnection and the packet acknowledged, said information indicating thecontent of the traffic control for every connection is registered insaid management table for every type of said packet.
 22. A computerprogram according to claim 21, after the acknowledging step, furthercausing said computer to perform the step of: acknowledging the type ofsaid received packet in response to a protocol information indicating aprotocol used in communication of said packet and an applicationinformation indicating an application of a communication terminal forprocessing the content of said packet.
 23. A computer program accordingto claim 22, after the acknowledging step, further causing said computerto perform the step of: acknowledging the type of packet in reference toa priority information included in said received packet, the priorityinformation desired by a terminal device transmitting said packetindicates a degree of priority of the processing on said packet.
 24. Amanagement terminal for managing networks, said networks each beingconnected to at least one communication terminal and at least two routerdevices for connecting said networks to each other, said managementterminal performs the steps of: generating a managing packet includinginformation for a permit list in said router devices indicating eitheran allowed opening or not-allowed opening of a connection for everyconnection and information for a management table in said router devicesindicating the content of a traffic control performed for said everyconnection of said communication terminals; and transmitting saidmanaging packet to said router devices.
 25. A computer program accordingto claim 19 wherein said storage medium is included in a serverconnected to a network which is connected to a plurality of computers;and wherein said server transfers said computer program stored on saidstorage medium to said computers connected to said network.